Continued approval may be contingent upon verification of clinical benefit in a confirmatory trial The Food and Drug Administration (FDA) has granted accelerated approval to Brukinsa (zanubrutinib; BeiGene USA) for the treatment of adult patients with mantle cell lymphoma who have received at least 1 prior therapy.
Zanubrutinib is a small molecule inhibitor of Bruton tyrosine kinase (BTK) that works by forming a covalent bond with a cysteine residue in the BTK active site, leading to inhibition of BTK activity. In nonclinical studies, zanubrutinib inhibited malignant B-cell proliferation and reduced tumor growth.
The approval was based on data from a single-arm, open-label, multicenter phase 2 trial that evaluated the safety and efficacy Brukinsa in 86 patients with MCL who had received at least 1 prior therapy. Patients received Brukinsa 160mg twice daily until disease progression or unacceptable toxicity for up to 3 years. The primary end point was the rate of objective response; secondary end points included progression free survival (PFS), 6-month PFS rate, duration of response (DOR), overall survival (OS), and the safety and tolerability of Brukinsa.
Results showed 84% (95% CI: 74, 91) of patients demonstrated tumor shrinkage with a median DOR of 19.5 months. A complete response was observed in 59% of patients and 24% of patients achieved a partial response. Additionally, a single-arm, open-label, multicenter phase 1/2 trial also supported the approval of Brukinsa (N=32); in this study, 84% (95% CI: 67, 95) of patients had tumor shrinkage with a median DOR of 18.5 months.
With regard to safety, the most common adverse reactions included decreased neutrophil count, decreased platelet count, upper respiratory tract infection, decreased white blood cell count, decreased hemoglobin, rash, bruising, diarrhea and cough.
“Mantle cell lymphoma usually responds well to initial treatment, but eventually returns or stops responding, and the cancer cells continue to grow,” said Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research. “For patients whose disease relapses or becomes refractory, secondary therapies may be successful in providing another remission, and today’s approval will provide patients with another treatment option.”
The FDA previously granted Breakthrough Therapy and Orphan Drug designations to Brukinsa. The product will be available in the coming weeks in 80mg strength capsules.
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